"Failed while preparing data" errors are quite common and I see them all the time when setting up TiVo's, although it is random so most people would not see it or simply instruct the TiVo to try again at which point the TiVo will succeed. I've never had to go to the lengths of clearing and deleting everything for it to be a success however.

In Leanne's case the problem of failing to download guide data but then being successful the next time is also common and again like I mentioned above simply initiating the "call" again usually works. The issue of no valid guide data could be that simply a reboot may correct things, or it may also mean the clock is warped - which it can very well be even if it has been "set" on a daily call.